Retinal ischemia and embolism - Etiologies and outcomes based on a prospective study

Objectives: To identify the most likely mechanisms of retinal ischemia and embolism in a hospital-referred population, and to determine the frequency of recurrent vascular events during the 3-month period following initial pr esentation. Methods. Consecutive patients presenting to 2 tertiary medical centers and their outpatient clinics were prospectively enrolled over a 22- month period. Eligible patients presented with histories of transient or pe rmanent monocular visual loss, or had evidence of asymptomatic retinal embo lism on routine ophthalmological examination. They underwent a rapid and st andardized evaluation that included imaging studies as well as blood tests, and follow-up was obtained at 1 and 3 months. Results: Seventy-seven patie nts were enrolled. Enrollment diagnoses consisted of amaurosis fugax (n = 3 2), asymptomatic retinal embolism (n = 34), and central or branch retinal a rtery occlusion (n = 11). Eight different presumed etiologies of retinal ar tery distribution embolism or hypoperfusion were identified. Extracranial i nternal carotid artery occlusion or more than 50% stenosis was observed in 17/77 (22.1%) cases, making it the largest etiologic subgroup. Uncommon but treatable conditions were identified in 8/77 (10.4%) patients, and an etio logic diagnosis could not be made in 35/77 (45.5%) patients. Recurrent even ts occurred in, respectively, 14/77 (18.2%) and 6/73 (8.2%) patients at the 1- and 3-month follow-ups. They included 2 infarcts and 2 deaths; ischemic events of the retina were more common than those involving the brain. Conc lusion: Severe stenosis of the extracranial internal carotid artery is the most common identified condition associated with retinal ischemia and embol ism, but a variety of other, potentially treatable, conditions can be diagn osed if appropriate and specific evaluations are conducted. The frequency o f recurrent vascular ischemic events is highest during the 1st month of fol low-up and decreases during the 2nd and 3rd months. Recurrences range from relatively innocuous episodes of amaurosis fugax to vascular death. Copyrig ht (C) 2001 S. Karger AG, Basel.